Photographic material



Oct. 29, 1940.

B. GASPAR 2,219,306

PHOTOGRAPHIG MATERIAL Filed Dec. 3. 1938 da.: Mavim/m?? zum .sem-usm am .quasi-Mmmm lmventor Patented Oct. 29, 1940 UNITED .STATES PHOTOGBAPHIC MATERIAL Bla Gaspar, Hollywood, Calif.

applicati@ December 3, 193s, serial No. 243,890 In Great Britain December 9, 1937 6C'laims.

The present invention relates to a photographic multilayer material for color photographic purposes. Some or all of the various light sensitive layers contain, already before the exposure, the

dye necessary for the formation of the ilnal image. As is known, such light-sensitive materials after exposure of the light sensitive layers, are converted into colored pictures by means oi local removaloi' the dyestui. If two or more 1g layers are arranged upon the same support, it is necessary to sensitize at least two of the layers for diierently colored light in order to produce the desired color selection picture in each individual layer with light corresponding to the sensitivity.

Now it is known, that an ordinary silver bromide emulsion is sensitive to blue light and remains so even if a predominant sensitivity to green, red or infrared is imparted to the emulsion 30 by the addition of a special color sensltizer. For this reason in a multilayer material composed of two or more silver halide layers at least one specially sensitized layer is sensitive not only to the light for which the layer is predominantly sensi- 25 tized, but also to blue light. For an analogous reason two emulsions are sensitive to green light, if the one contains a sensitizer for green and if the other one contains a panchromatic sensitizer or one which imparts a predominant sensitivity to ad red but in addition a noticeable sensitivity to green.

'Ihe sensitivity of two superimposed layers to the same light renders a correct color separation very dilcult and it is an object of the present 35 invention to restrict the action of light to that of the two layers which is ilrst hit by the light falling upon the composite layers. In a predyed multilayer material of the kind described, in which at least one light sensitive layer is sensitive n not only to light for which the layer is predominantly sensitive but also to light for which a superimposed light sensitive layer is to be exposed, the superimposed layer is, according to the present invention, dyed by a mixture of two different dyestuils of a color complementary to the sensitivity of this layer. lThe one of the dyestuis used for this purpose is resistant to the ordinary photographic treating solutions but capable of being selectively destroyed in proportion 50 to the exposure or the silver image. 'I'he other dyestui has substantially the same color but is easily removable by photographic treating solutions which do not remove the ilrst named dyestud'. This ilrst named dyestufi is used in a concentration which corresponds to the color intensity necessary or desired for reproducing the most intensely colored parts of the image. The removable dyestuif is used in such a concentration that the absorption of both dyestufs together is sucient for preventing any light of complementary color from entering the second layer.

Instead of coloring the superposed layer as a whole by a mixture of the two dyestuffs, the auxiliary dyestui may also be applied to the rear surface of the superposed layer or may be 10 incorporated into an intermediate layer between the two layers in question. In this case, therefore, the layer rst hit by the light is dyed by a dyestufl resistant to the ordinary photographic treating solutions and of a color complementary 1 to the color of the light to which this layer is sensitized, the dyestuff concentration in the layer corresponding to the color intensity required at the most intensely colored points of the image.

The properties of the layer allow the incident light to enter the colored layer and to penetrate it where the intensity has its maximum value. The penetrating light, however, is absorbed at the rear surface or in the intermediate layer by the auxiliary dyestui and thus the light-sensitive layer behind is effectively screened.

Example-Referring to the drawing, on a paper support there are coated in superposition a blue-green emulsion sensitized to red light, a magenta dyed emulsion sensitized to green and a yellow dyed blue-sensitive emulsion.

The yellow dyed emulsion is the top layer and contains the dyestuif Xylenewalkgelb G (Shultz Farbstofftabellen, volume 2) in the form of its 35 calcium salt in a concentration of 0.45 g. per sq. m. The same layer or a separate layer of plain gelatine arranged behind the same contains 1 to 2 g. per sq. m. of the dyestuff 4,4'- methenyl-bis-l (p-sulphophenyl)-3-methyl-py- 40 razolone-5 in the form of its triphenylguanidine salt.

A magenta layer then follows which contains 0.3 g. per sq. m. of Tuchechtbrillantrot 2B (a dyestuff supplied by the Gesellschaft fuer Chemische Industrie in Basle and similar to the dyestuff Polarbrillantrot B described in Brunner, Analyse der Azofarbstoie, Berlin 1929, page 113) in the form of its N-methyl-naphthoquinolinium salt, which may conveniently be formed by the action of a solution containing N-methyl-quinoliniummethyl sulphonate on the dyestu. The layer is formed by an ordinary blue-sensitive emulsion sensitized to green light by any suitable greensensitizer, and a magenta dyestui, such as the Pontainine Sky Blue 5BX (Schultz Farbstotabellen, 1931, '7th ed. vol. 1. No. 513). The dyestuff is used in a concentration of about 0.35 g. per sq. m. emulsion and the layer is applied to the paper support. The dyestui 4,4'metheny1 bis i 1 (p sulphophenyl) 3 -methyl-pyrazolone- 5l and other suitable decolorisable dyestuiis are described in my application Ser. 240,860 iiled Nov. 16, 1938. The material may be exposed behind colored or black and white positive part images or behind a multi-color master-positive of the additive or subtractive type. The auxiliary dyestuffs are decolorised after exposure of the three layer material preferably by a developer of alkaline reaction and the image-forming dyestuffs are locally destroyed after development oi' the silver images, for example, by an acid thiocarbamide solution or by a solution containing 5% hydrobromic acid. If necessary the silver is afterwards removed from the dyestuff image thus obtained.

What is claimed is:

1. A multilayer light-sensitivematerial, comprising a support carrying a plurality of superposed silver halide emulsion layers sensitive to light of diierent colors, at least one of the layers being dyed by a dye which is fast to ordinaryphotographic treating solutions but capable -of being locally bleached in the presence of a metallic silver image and which absorbs the total spectral range of light rays for which the layer is predominantly sensitized, a second one of said plurality of superposed light-sensitive layers arranged behind said fast dyed layer being transmittant for and sensitive to such light, and a filter dye of substantially the same color as said fast dye being present in a layer in front of the said second layer but not in front of said fast dyed layer, said lter dye being removable by an agent which does not remove said fast dye.

2. A multilayer light-sensitive material, comprising a support carrying' a plurality of superposed silver halide emulsion layers sensitive to light of different colors, at least one of the layers being dyed by a dye .which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of a metallic silver image and which absorbs the total spectral range of light rays for which the layer is predominantly sensitized, a second one of said plurality of superposed light-sensitive layers arranged behind said fast dyed layer being transmittant for and sensitive to such light, and a lter dye of substantially the same color as said fast dye being present in a colloid'layer arranged between said fast dyed layer and said second light-sensitive layer, said lter dye being removable by an agent which does not remove saidV fast dye.

3. A multilayer light-sensitive material, comprising a support carrying a plurality of superposed silver halide emulsion layers sensitive to light of different colors, at least one of the layers being dyed by a dye which is fast to ordinary photographic treating solutions but capable of being'locally bleached in the presence of a metallic silver image and which absorbs the total spectral range of light rays for which the layer is predominantly sensitized, a second one of said plurality of superposed light-sensitive layers arranged behind said fast dyed layer being transmittant for and sensitive to such light, and a filter dye of substantially the same color as said fast dye being present in the said fast dyed lightsensitive emulsion layer, said lter dye being removable by an agent which does not remove said fast dye.

4. A multilayer light-sensitive material, comprising a support carrying a plurality of superposed silver halide emulsion layers sensitive to light of different colors, at lea'st one of the layers being dyed by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of a metallic silver image and which absorbs the total spectral range of light rays for which the layer is predominantly sensitized, a second one of said plurality of superposed light-sensitive layers arranged behind said fast dyed layer being transmittant for and sensitive to such light, and a fil-ter dye of substantially the same color as said fast dye and which is capable of being destroyed by a photographic developer which does not remove the said fast dye, said lter dye being present in a layer in front of the said second layer but not in front of the said fast dyed layer.

Y5. A multilayer light-sensitive material, comprising a support carrying a plurality of super-4 posed silver halide emulsion layers sensitive to light of different colors, at least one of the layers being dyed by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of a metallic silver image and which absorbs the total spectral range of light rays for which the layer is predominantly sensitized, a second one oi' said plurality of superposed light-sensitive layers arranged behind said fast dyed layer being transmittant for and sensitive to such light, and a lter dye of substantially the same color as said fast dye being present in a layer in front of the said second layer but not in front of said fast dyed layer, the absorption of said filter dye being greater than the absorption of said fast dye and said lter dye being removable by an agent which does not remove said fast dye.

6. A multilayer light-sensitive material, comprising a support carrying a plurality o! superposed silver halide emulsion layers sensitive to light of different colors, at least one of the layers being dyed by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of a metallic silver image and which absorbs the total spectral range of light rays for which the layer is predominantly sensitized, a second one of said plurality oi' superposed light-sensitive layers arranged behind said fast dyed layer being transmittant for and sensitive to such light, and a filter dye of substantially the same color as said fast dye being present in the said fast dyed lightsensitive emulsion layer, the absorption of said lter dye being greater -than the absorption of said fast dye and said filter dye being removable by an agent which does not remove said fast dye.

BELA GASPAR. 

